Method for fixing prosthetic implants in a living body

ABSTRACT

A device and method for facilitating the rapid positive fixation of implanted prosthetic members in a living body. The device comprises a tubular sleeve of deformable material to which the prosthetic member is secured and which is capable of being expanded radially into intimate engagement with surrounding tissue. The fixation device and prosthetic member, such as heart valve, vessel graft, etc., are prepared by assembly prior to surgery. The assembly may be rapidly introduced into the transplant situs during surgery and secured in place by expansion of the deformable sleeve by use of an expansion tool.

United States Patent Ersek 1 Apr. 25, 1972 METHOD FOR FIXING PROSTHETICIMPLANTS IN A LIVING BODY Robert A. Ersek, St. Louis Park, Minn.

The Regents of the University of Minnesota, Minneapolis, Minn.

Filed: May 8, 1970 Appl. No.: 35,815

Inventor:

Assignee:

U.S. Cl ..3/l, 3/DIG. l, 3/D1G. 3, 128/334 R Int. Cl. ..A6lf l/22, A6lfl/24 Field ofSearch l28/334 R, 334 C, 341, 343, 128/348; 3/1, DIG. l,DIG. 3

References Cited UNITED STATES PATENTS 5/1970 Dibelius.... ..l28/348Noble ..l28/334 R FOREIGN PATENTS OR APPLICATIONS 180,750 9/1966 U.S.S.R..3/DIG. 3

Primary Examiner-Richard A. Gaudet Assistant Examiner-Ronald L. FrinksAttorney-Burd, Braddock & Bartz [5 7] ABSTRACT A device and method forfacilitating the rapid positive fixation of implanted prosthetic membersin a living body. The device comprises a tubular sleeve of deformablematerial to which the prosthetic member is secured and which is capableof being expanded radially into intimate engagement withsurrounding'tissue. The fixation device and prosthetic member,

such as heart valve, vessel graft, etc., are prepared by assembly priorto surgery. The assembly may be rapidly introduced into the transplantsitus during surgery and secured in place by expansion of the deformablesleeve by use of an expansion tool.

3 Claims, 9 Drawing Figures PATENTEUAPR 25 m2 sum 1 or 2 AT TORNE-YSPATENTEDAPR 25 m2 57, 744 SHEET 2 OF 2 INVENTOR,

ATTORNEYS METHOD FOR FIXING PROSTIIETIC IMPLANTS INA t LIVING BODY Thisinvention relates to a device and method for the rapid positive fixationof implanted prosthetic members in a living being. Many thousands ofimplants of prosthetic members,

either artificial members or homografts or grafts from other animalspecies are made annually. Vessel grafts and heart valve implants arebecoming commonplace. Transplantation of large organs such as the heart,lungs, liver, etc. is taking sue leaving no exposed surface for theformation of clots and thrombi. 1

According to the prior art, artificial heart valves are installed by thecareful placing of a plurality of stitches around the rim of tissue thatwill house the valve. These'stitches are passed through a suture ringaroundthe outside of the heart valve. The valve to be implanted is heldoutside of the heart 6 or 8 inches and each stitch is brought up throughthe suture ring while the valve is still so held. When the sewing isfinished, the valve stands some distance above the heart and has 20 orsutures going down to the tissue where it will finally rest. The suturesare held tight and the heart valve is slid down them into place and eachsuture is then individually tied. This process takes 30 to 45 minutes inthe best hands and from an hour to an hour and one-half in the less thenbest.

In the case of the transplantation of a graft valve from another patientor from an animal, sewing takes more than an hour. Although excellentresults have been reported with these transplanted valves, few surgeonsare using them today because of the great time that must be taken to sewthem in. Valve installation takes place while the patient is on anartificial heart-lung machineand every minute is very important.

One form of prior art heart valve is available wherein a caged ballvalve is provided in its outer rim with a plurality of radially.extending teeth which by screw means are caused to engage the aorticwall. Such valves, though expensive, are satisfactory where there is avery tight initial fit and where the aortic wall is of uniformconsistency and size, conditions which cannot always be depended upon toexist. Accordingly, problems have arisen relating to aortic incompetencedue to blood flow working its way between the prosthesis and the aorticwall in the many instances where no positive fixation is achieved by thetooth members.

The device of the present invention permits instant and positivefixation of heart valves, vessel grafts and other prosthetic members.The valve or other prosthetic member is prepared for implantation byattachment to the openwork sleeve. The valve and its skirt composed ofthe sleeve is assembled on an expanding tool device. This assembly canbe quickly and easily forced into place and the tubular sleeve expandedto hold the valve or other member in place. This is done in a smallfraction of the time required for other transplants so that in manyinstances use of the heart-lung machine is not required. The fixationsleeve expands so that a snug fit is assured regardless of the size,shape or consistency of the tissue wall at the implantation situs. Sincethe sleeve becomes incorporated into the tissue wall, no foreignmaterial is left in contact with the blood, as opposed to prior artdevices.

The invention is illustrated by the accompanying drawings in which:

FIG. I is a schematic view showing three stages of the grafting of anartificial bifurcation vessel graft utilizing the fixation deviceaccording to the present invention;

FIG. 2 is a perspective schematic view of one modified form ofprosthetic fixation device;

FIG. 3, is aperspective view of another modification;

FIG. 4 is a'perspective view of a furthermodification;

FIG. 5 is a schematic representation of a portion of the perimeter ofany one of the devices of the preceding FIGS., as seen in transversesection;

FIG. 6 is an elevation of one form of expanding tool which may beutilized with the fixation device;

FIG. 7 is a fragmentary elevation of the operating end of the expandingtool showing the tool in expanded condition;

FIG. 8 is a perspective elevational'view with the upper half of thefixation device in section, and showing the fixation device with a heartvalve attached for implantation; and FIG. 9 is a top plan view of theassembly of FIG. 8.

Referring to the drawings, and particularly to FIG. 1, there is shownschematically one manner in which the prosthesis fixation deviceaccording to the present invention is used. This use is illustratedwithrespect to the implantation of an artificial bifurcated aortic Dacrongraft,indicated generally at 10, between the severed aorta 11, shownwith a Satinsky clamp Ipreventing flow,-and the common iliac arteries 13and '14. A

completed joint is shown between the artery' 13' and. one branch 15 ofthe artificial vesseltransplant. The ends of themtery and prosthesis arein butting relation held by an expanded fixation sleeve, indicatedgenerally at 16, within the' host'- prosthesis junction.- A similarsleeve 16 is shown partially within the branch 17 of the prosthesis 10about to be connected to the artery 14.

The manner in which the junction is made is shown with respect to thesevered end of the aorta 11. An expandable sleeve fixation device 16 isshown extending from the end of the artificial vessel graft 10 withabout half of its length engaging the inside wall of the graft. The head.of an expander tool,

indicated generally at 18, whose tubular barrel 19 extends through aslit 20 in the graft, is positioned within the sleeve. A

tapered tip 21 placed onv .the end of the expanding tool facilitatesentry of the assembled graft, tool and fixation device 16 into theaorta. When in place, with the ends of aorta 11 and graft 10' butting,the sleeve is expanded by operation of the expanding tool to force thefenestrations of the sleeve into the wall of the aorta to achieve aleak-proof union and forcing the walls of the sleeve into tighterengagement with the inside wall of the graft).

After "the sleeve is expanded, the tool is withdrawn. 'A

smaller headed tool is inserted through slit 20 fromthe oppositedirection to within the fixation device '16 of lesser diameter forconnection with artery 14. The exposed end of sleeve is expanded tomakethe joint. The tool is withdrawn,

sleeve 16 is inserted into the lumen of the artery 14 and the slit 20 isclamped shut and clamp 12 is removed to permit resumption of bloodflow.'The entire transplant can be made in a matter of a very fewminutes to the point of restoration of the blood supply. Thelongitudinal slit in the graft may then be sewn closed at leisure inconfidence that the blood is being supplied distal to the graft site. i

The tubular sleeve 16 is made of deformable material such panded metalsheeting which is produced by forming a series of staggered parallelslits in an impervious metal sheet and then stretching the sheet in adirection perpendicular to the slits to open the slits into aperturesand expand the metal sheet in that direction 'while contracting itslightly in the opposite direction. The stretching operation by whichthe metal sheet is expanded imparts a twist or bend to the undulatingflat ribbonlike portions 22 of the metal sheet separating thediamondshaped apertures 23 which are generally uniformly sized anddistributed. This twisting or bending of the metal members 22 betweenadjacent apertures imparts an angle or direction to the aperturesthemselves and to the ribbon-like members.

The expanded metal sheeting is desirably not flattened prior to forminginto a sleeve. The result, as seen schematically in FIG. 5, is that theribbon-like portions 22 of the sleeve extend angularly relative to theperimeter of the sleeve providing a multitude of narrow projecting edgeswhich embed themselves into the tissue wall upon expansion of thesleeve. After being formed with the members 22 extending generallylongitudinally, the sleeve is desirably spot welded to form alongitudinal seam. The tubular sleeve may be circular, oval, orpolygonal (hexagonal, octagonal or the like) in cross-section. Thecross-sectional area may be uniform along the length of the sleeve or itmay vary, giving the sleeve generally a barrel shape or that of atruncated cone. The edges may be cuffed if desired or simply smoothed tofacilitate entry. The sleeve may easily be expanded by about 50 percentbeyond its original diameter. The sleeves are formed to be a sizeappropriate for the implant being made. The strands 22 and apertures 23are sized proportionately.

Because of the twisted relation of the ribbon-like portions of thesleeve, protrusion of the vessel lining is facilitated with the resultthat very little metal is actually in contact with the blood stream.Experimentally it has been determined that within a few seconds a fineclot layer is laid down over the stainless steel struts forming aphysiological bridge from the islands of intima where the vessel liningprotrudes through the apertures in the sleeve.

Instead of metal, the tubular fixation sleeve may be formed from othernatural or synthetic materials having the requisite propertiesandcharacteristics permitting the sleeve to be ex panded into secureattachment with surrounding tissue. Desirably the material is one whichis capable of being absorbed over an extended period of time by thetissue to which the sleeve is attached. A number of such absorbablematerials are known.

In the form of fixation device shown in FIG. 2, sleeve 16A is providedwith a plurality of circular holes 24 (which are of larger area thanapertures 23) punched through the openwork wall around the sleeveadjacent one end to allow for the ostia of the coronary arteries.

In FIG. 3, a modified form of sleeve 16B is provided with a plurality ofrelatively large rectangular openings 25 extending longitudinally topermit exposure of wide areas around the coronary artery ostia. Thisform of fixation device is intended for the implantation of heartvalves. The valve is hung with its commissures secured along the upperand lower ring portions 26 and 27, respectively, whose widths are aboutone-eighth to one-fourth the length of the sleeve.

In FIG. 4, the fixation device includes a plurality of longitudinal wirestruts 28 separating two expandable and relatively narrow metal meshring sections 29 and 30. A three-pronged commissure valve is inserted inthe upper expandable ring section 29 and secured to the bottom mesh ring30 circumferentially.

A variety of expanding devices may be used to set the fixation devicesin place. One form of such tool is shown in FIG. 6. The device includesa pistol-grip handle 31 and a trigger-like operating lever 32 pivotedtherein. An elongated tubular barrel 19 extends out from the handlemeans. A concentric rod 33 extends through the handle 31 and barrel 19terminating in a fitting 34 beyond the muzzle end of barrel 19 at itsforward tip. Expansion means, comprised of a pair of resilient rings 35,

I each held between a pair of washers 36 and held spaced apart by arigid spacer ring 37, are disposed between the muzzle end of barrel l9and tip fitting 33. Operation of the lever 32 by gripping and squeezingto move it toward the handle causes rod 33 to shorten its exposed lengthin relation to barrel 19 such that squeezing force causes the resilientrings to decrease their longitudinal dimensions. Being non-compressible,they expand radially outwardly increasing their lateral dimensions, asshown in FIG. 7. In this way, a predictable dependable amount ofexpansion can be achieved. The breech end of rod 33 is threaded andfitted with a knurled knob 38. The heel 39 of operating lever 32 bearingagainst a spacer tube 40, which in turn bears against knob 38, causesthe relative movement between barrel l9 and rod 33. Alternatively, forcemay be exerted simply by rotation of knob 38 and adjustment of theatrest force exerted upon the expansion rings may be made. One, two ormore expandable rings 35 may be used. The pattern of expansion can bepredetermined as desired by selection of appropriate spacing betweenthose rings.

When used for the installation of artificial vessel grafts made ofDacron, Teflon or similar artificial materials, the fixation sleeve isattached to the vessel graft some time prior to surgery and alongitudinal slit is made in the middle of the graft for theintroduction of the expansion tool. At the time of surgery, the ends ofthe vessel to be grafted are secured through simple stay stitches orsmall clamps so that the fixation sleeve can be introduced thereto. Theexpander tool is in place in one of the sleeves at the time ofintroduction. This sleeve is then expanded in situ and the expander toolis removed through the longitudinal slit, turned around and used toexpand the fixation sleeve at the other end and again removed. Thelongitudinal slit is clamped and the clamps or stitches securing thevessels to be grafted are removed to restore the blood flow. Very rapidfixation of vessel grafts is thus possible.

In FIG. 8 there is shown an aortic heart valve 45 in place in a fixationsleeve 16. The rim of valve 45 adjacent the cusps 46 is attached bysutures 47 to the sleeve near one end. A segment of the donor aorta 48is attached by sutures 49 near the other end of sleeve 16. The opening50 in the aorta wall for a coronary artery can be matched with thecorresponding opening in the wall of the donee aorta.

When used for the fixation of heart valves, whether a transplant orartificial, the valve is secured within the fixation sleeve prior tosurgery and the sleeve is assembled in the expansion tool. Then, at thetime of surgery, the sleeve is rapidly expanded into place and the toolwithdrawn. When used for implantation of heart valves in the aorticposition, a total introduction time of only a few minutes is necessary.This means that an aortic valve may be placed without use of aheart-lung machine. Inflow of blood into the heart is occluded byplacing clamps across the appropriate vessels. A longitudinal slit(aortotomy) is placed in the aorta just a few centimeters above where itbegins. This slit'is opened and the existing defective valve is removed.The new valve housed in the expandable sleeve is then placed in positionand the sleeve is expanded in one stroke of the expanding tool. Theexpansion tool is then removed through the aortic slit and a clampplaced over it, thus allowing the restoration of blood flow so that onlya few minutes total introduction time is required. The aortotomy canthen be repaired at leisure after the heart has taken over its pumpingfunction.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made without departing from the spiritand scope thereof. The specific embodiments described are given by wayof example only and the invention is limited only by the terms of theappended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A method for rapidly and positively fixing an inplanted prostheticdevice in a living body which comprises:

A. securing the prosthetic device to be implanted to at least oneopenwork tubular sleeve of non-toxic deformable material compatible withbody fluids and capable of being expanded radially, said sleeve being ofa diameter corresponding to the prosthetic member to be implanted andadapted for attachment to the prosthetic member, and including aplurality of longitudinally extending ribbon-like undulating portionsdisposed angularly with respect to the perimeter of said sleeve andinterconnected to define a plurality of staggered closely spacedapertures,

B. introducing the sleeve and prosthetic device into a preparedtransplant situs, and

C. expanding the sleeve radially outwardly against the tissue walls ofsaid situs and forcing the undulating ribbon-like portions of the sleeveinto intimate engagement therewith, whereby the tissue may grow throughand around the sleeve to cover the same.

2. A method according to claim 1 further characterized in that:

A. said prosthetic device to be implanted is a vessel graft,

B. said openwork sleeve is inserted partially and secured in each end ofsaid vessel graft leaving an exposed portion of sleeve extendingtherefrom,

C. said graft is provided with a longitudinal opening to receive asleeve expanding tool;

D. said prosthetic device and sleeves are joined to the host vessels tobe grafted by introduction of the exposed portions of said sleeves intothe severed host vessels, and

E. the sleeves are expanded radially outwardly into intimate engagementwith the walls of said vessels and said graft.

3. A method according to claim 1 further characterized in that:

A. said prosthetic device to be implanted is a heart valve,

B. said valve is secured within one end of said sleeve,

C. said sleeve and valve are introduced into the situs of the defectivevalve to be replaced, and

D. said sleeve is expanded into engagement with the surrounding tissue.

1. A method for rapidly and positively fixing an inplanted prostheticdevice in a living body which comprises: A. securing the prostheticdevice to be implanted to at least one openwork tubular sleeve ofnon-toxic deformable material compatible with body fluids and capable ofbeing expanded radially, said sleeve being of a diameter correspondingto the prosthetic member to be implanted and adapted for attachment tothe prosthetic member, and including a plurality of longitudinallyextending ribbon-like undulating portions disposed angularly withrespect to the perimeter of said sleeve and interconnected to define aplurality of staggered closely spaced apertures, B. introducing thesleeve and prosthetic device into a prepared transplant situs, and C.expanding the sleeve radially outwardly against the tissue walls of saidsitus and forcing the undulating ribbon-like portions of the sleeve intointimate engagement therewith, whereby the tissue may grow through andaround the sleeve to cover the same.
 2. A method according to claim 1further characterized in that: A. said prosthetic device to be implantedis a vessel graft, B. said openwork sleeve is inserted partially andsecured in each end of said vessel graft leaving an exposed portion ofsleeve extending therefrom, C. said graft is provided with alongitudinal opening to receive a sleeve expanding tool; D. saidprosthetic device and sleeves are joined to the host vessels to begrafted by introduction of the exposed portions of said sleeves into thesevered host vessels, and E. the sleeves are expanded radially outwardlyinto intimate engagement with the walls of said vessels and said graft.3. A method according to claim 1 further characterized in that: A. saidprosthetic device to be implanted is a heart valve, B. said valve issecured within one end of said sleeve, C. said sleeve and valve areintroduced into the situs of the defective valve to be replaced, and D.said sleeve is expanded into engagement with the surrounding tissue.